Coil design

1. Definitions



Definition of the coil – Case of Circular wires
1 Selection of the STATOR subset: WINDING panel (Click on the icon WINDING)
2 Coil settings allows the user to describe the coil composition (turns, wires, dimensions) and how to fill the slot.
3 Definition of the wire topology, Circular or Rectangular
4 Choice of the method to fill the slot:

Three ways are allowed to fill the slot: Orthocyclic, Random, Layer.

See below illustrations.

5 Choice of the method to group the elementary wires.

Three ways allow to fill the slot: Grouped, Horizontal, Vertical.

See below illustrations.

6 Description of the coil (turns, wires in hand) and dimensions of elementary wires + twist options


Definition of the coil – Case of rectangular wires
1 Selection of the STATOR subset: WINDING panel (Click on the icon WINDING)
2 Coil settings allows the user to describe the coil composition (turns, wires, dimensions) and how to fill the slot.
3 Definition of the wire topology, Circular or Rectangular
4 Choice of the method to group the elementary wires.

Three ways allow to fill the slot: Horizontal, Vertical.

See below illustrations.

5 Description of the coil (turns, wires in hand) and dimensions of elementary wires

The following inputs define the coil and how is filled the slots

Label Symbol Tooltip, note, formula
Wire topology * Wire topology, Circular or Rectangular.
Slot filling * Three ways are allowed to fill the slot: Orthocyclic, Random, Layer

See below illustrations

Conductor grouping method * Three ways are allowed to fill the slot: Grouped, Horizontal, Vertical

See below illustrations

No. turns per coil Turns Number of turns per coil.
No. wires in hand Nwires Number of wires in parallel in a conductor (per turn) i.e. number of wires in parallel in each conductor.
Wire diameter Wire diameter (without insulation), for circular wire (1)
Wire width W wire Wire width (without insulation), for rectangular shape type wire
Wire height H wire Wire height (without insulation), for rectangular shape type wire
Inter-wire space w//w Minimum distance between insulated wires to be considered for modelling inside the Flux2D environment.

When there is no wire insulation, Inter-wire space represents the minimum distance between the bar wires(2)

Twisted wires * The wires can be twisted inside the conductor.
Twisted conductors * The conductors can be twisted inside the slot.

1) Different ways are available to choose the wire diameter:

  • Directly entering the value of the wire diameter (without insulation)
  • Choose the diameter from the American Wire Gauge table in which available wire diameters are listed (without insulation)
  • Choose the diameter from the Metric Wire Gauge table in which available wire diameters are listed (without insulation)


1 Multiple choices with a scrolling selection bar for selecting the wire diameter
2 Three ways are available for defining the dimensions of the wire diameter:
  • Write the value of the wire diameter or to select it from the two below tables
  • American Wire Gauge table in which available wire diameters are listed (without insulation)
  • Metric Wire Gauge table in which available wire diameters are listed (without insulation)

2) Illustration of inter-wire space

This value is considered in Motor factory for computing the filling factor, and while exporting a model into Flux environment (EXPORT area) for building the corresponding finite element model.



Illustration of inter-wire space
1 Default value for inter-wire space and the corresponding pictorial display.
2 Impact of a higher value for inter-wire space

3) Twisted conductors and wires

While defining the coil in the design / Winding area, it is possible to twist the wires inside the conductors between the forward and return sections of the coil. It is also possible to twist the conductors between the forward and return sections of the coil.

It is possible to twist both the wires inside the coil and the conductors between the forward and return sections of the coil.

The four illustrations of what it is possible to do are presented below.



Neither the wires nor the conductors are twisted


The wires are twisted inside the conductors.

The direction of the gradated conductor color indicates the orientation of the twist.



The conductors are twisted between the forward and return sections of the coil.

The conductor colors indicate the position of conductors



The wires are twisted inside the conductors and

the conductors are twisted between the forward and return sections of the coil.

2. Relevance of the slot filling

When the number of wires are higher than allowed by the free space of the slot, the wires are grayed. This is to inform the user that the number of wires must be decreased.

In that case, the design of the winding is not possible; the machine cannot be built or tested.





Grayed circular shape type wire Grayed rectangular shape type wire

Motor Factory Design environment icon and winding icon in the Stator section are colored in red. This means that a design fault exists, and must be corrected in the winding section of the design environment.



Motor Factory Design environment Icon and the winding icon in the Stator section are colored in red.= a design fault must be corrected

The tests cannot be performed; the tooltip message indicates that the slot filling is not valid, and that the user must modify the slot filling parameters to unlock the test.

At the same time, a warning message indicates that there is not enough space for the specified number of wires. The allowed number of wires are mentioned in comparison with the targeted ones.



The tests cannot be performed